<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 600px;
            height: 300px;
            border: 1px solid red;
            background-image: radial-gradient(
                circle 300px at bottom center,
                white 40%,
                pink 50%,
                pink 55%,
                red 60%,
                red 65%,
                orange 70%,
                orange 75%,
                skyblue 80%,
                skyblue 85%,
                yellow 90%,
                yellow 100%,
                transparent
                
            );
            
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>